Characterization of an Iron-Oxide-Based Catalyst Used for Catalytic Cracking of Heavy Oil with Steam

Characterization of a complex metal oxide catalyst (Fe, Zr, and Al) used for catalytic cracking of petroleum residual oil with steam was examined. Heavy oil fractions were oxidatively cracked on the catalyst, producing light oil, gas, and carbonaceous residue. Vacuum residue (VR) conversion was maintained for 2-6 h using adequate contents of Fe, Zr, and Al in the catalyst. Although consumption of lattice oxygen within the catalyst caused partial reduction of iron oxide in the initial stage of the reaction, oxygen species were effectively incorporated into the iron oxide lattice from steam, which reacted with heavy oil, suppressing further reduction of iron oxide. The contents of Fe, Zr, and Al in the catalyst were not homogeneous. Some coke was deposited in the region where the Fe content was low, resulting in pore plugging. This pore plugging slightly decreased light oil yields after 6 h, but VR conversion was maintained. Almost no coke was deposited in the region where iron oxide was the main component, and Zr and Al contents were low in the complex metal oxide catalyst. The heavy oil fractions were oxidatively cracked effectively in this region.